1. Field of the Invention
The present invention relates to a carriage for liquid crystal modules in which liquid crystal modules are loaded and aging tests or the like are carried out in the manufacture of the liquid crystal display device.
2. Description of the Related Art
In the manufacture of a color liquid crystal display device, an aging test is carried out after module assembly has been completed, and there has been proposed in prior art a carriage for aging that is designed to reduce the number of processes and improving the work efficiency during the aging test by adopting a carriage structure that allows modules to be transported (see Japanese Laid-Open Patent Application Nos. 2002-5977 and 2002-19612, for example). FIG. 8A is a front view that schematically shows the carriage for aging that is described in Japanese Laid-Open Patent Application No. 2002-5977, and FIG. 8B is a side view of the same. The carriage for aging 110 described in Japanese Laid-Open Patent Application No. 2002-5977 is provided with a product rack 102 on which a plurality of modules 103 can be mounted on the upper tier of the portable carriage main body 101, as shown in FIGS. 8A and 8B. The front side of the carriage main body 101 is provided with an operating panel 106 for setting voltages and signals that are suitable for the specifications of the modules 103.
The middle and lower tiers of the carriage main body 101 are provided with a DC power supply 104 for driving the modules 103, a digital signal source 105 that generates digital signals for driving the modules 103, a control circuit 107 for controlling the power and signals that are output to the modules 103 on the basis of values set using the operating panel 106, and an output circuit 108 for distributing a plurality of drive signals and feeding the signals to the modules 103. The operating panel 106 is provided with a power supply input connector 109 for connecting an external power supply cable 111.
Described next is the operation of the carriage for aging 110, more specifically, a conventional method for manufacturing a liquid crystal display device in which the carriage for aging 110 is used. FIG. 9 is a flowchart showing a conventional method for manufacturing a liquid crystal display device in which the carriage for aging 110 is used. FIG. 9 shows only the aging test and the preceding and subsequent circuit adjustment and display inspection operations. When the assembly of the modules 103 is completed (step S101) in the case that a conventional carriage for aging 110 is used, the modules 103 are placed on a transport carriage and transported to the circuit adjustment step (step S102), as shown in FIG. 9. In the circuit adjustment step, the modules 103 are placed one at a time on an inspection stand on a work desk, and signal and power cables are connected to the modules 103 (step S103). A prescribed pattern is thereafter displayed on the modules by operating a signal generator and a DC power supply to carry out circuit adjustment (step S104). After circuit adjustment is completed, the signal and power cables are detached from the modules 103 (step S105).
Next, the modules 103 are placed on a transport carriage and transported to the aging step (step S106). In the aging step, a plurality of modules 103 are mounted on the product rack 102 on the carriage main body 101 (step S107). The signal and power cables provided to the product rack 102 are thereafter connected to the modules 103, and the external power supply cable 114 is connected to the power supply input connector 109 provided to the carriage main body 101 (step S108). Next, the voltages and signals for driving the modules 103 are set in the operating panel 106, and aging testing is carried out (step S109). At this time, power and signals are output from the control circuit 107 in accordance with the conditions that have been set by using the operating panel 106 in the carriage for aging 110. The output for driving the modules is distributed by the output circuit 108 and is fed to each of the plurality of modules 103. A plurality of modules 103 can thereby be simultaneously subjected to aging testing. When high-temperature aging testing is carried out, the settings are input using operating panel 106, after which the carriage for aging 110 is placed in a high-temperature atmosphere.
When display inspection is carried out after aging testing, the signal and power cables connected to the modules 103 are detached, and the external power supply cable 114 is detached from the power supply input connector 109 (step S110). The modules 103 are then reloaded onto the transport carriage and are carried to the display inspection step (step S111). In the display inspection step, the modules 103 are loaded one by one onto the inspection stand on the work table, and the signal and power cables are connected to the modules 103 (step S112), after which the modules are lighted up or prescribed patterns are displayed on the modules by operating the signal generator and DC power supply to carry out the display inspection (step S113). After the display inspection operation is completed, the signal and power cables are detached from the modules 103 (step S114).
Disclosed in Japanese Laid-Open Patent Application No. 2002-19612 is a carriage for aging that is provided with a plurality of drawer shelves within the carriage main body that can travel on wheels, and in which the liquid crystal modules are set on the drawer shelves and the aging test is carried out. The carriage for aging is configured so that the display state of the modules can be visually examined by pulling out the drawer shelves.
However, the prior art described above has the following problems. The carriage for aging of the prior art described in Japanese Laid-Open Patent Application No. 2002-5977 cannot carry out display inspection that is to be performed from the front of the modules because the modules are disposed in a single row front to back. With the carriage for aging of the prior art described in Japanese Laid-Open Patent Application No. 2002-5977, circuit adjustment cannot be carried out because the flicker volume disposed on the front or back side of the modules cannot be adjusted. In the carriage for aging described in Japanese Laid-Open Patent Application No. 2002-19612, the display surface can be checked, but when the flicker volume is disposed on the back side, circuit adjustment cannot be carried out. Since the voltage applied to the liquid crystal modules and the patterns that are displayed are each different for circuit adjustment, aging testing, and display inspection, circuit adjustment and display inspection cannot be carried out with the power supply and signal source for aging testing that are provided to the carriage of Japanese Laid-Open Patent Application Nos. 2002-5977 and 2002-19612.
Thus, with the conventional carriages for aging described in Japanese Laid-Open Patent Application Nos. 2002-5977 and 2002-19612, only aging testing can be performed. With the conventional method for manufacturing liquid crystal displays, extra labor is required and the number of steps and personnel increases since attaching and detaching operations of the modules must be carried out for each of the circuit adjustment, aging testing, and display inspection steps which are carried out after the completion of module assembly. Also, since the modules are attached and detached many times, defects occur more readily due to connector damage. Furthermore, in the conventional methods for manufacturing liquid crystal displays, since the signal and power cables that are connected to the modules are different for each step, the number of cables that are used is considerable. These problems can be prevented by sharing cables that are used in each step, but doing so increases the chance that the cables and connectors will be damaged due to the greater number of times that a single cable is attached and detached.